Exposes the recently added updateInventory method.

We've decided to expose updateInventory as a temporary work-around for
 the inventory not updating issue we're aware of. The reasoning behind
 this is that addressing it properly will take some time and work and
 as this is clearly a roadblock for some plugin authors, the delay is
 not really acceptable.

By: EvilSeph <evilseph@unaligned.org>

paper-api/src/main/java/org/bukkit/entity/Player.java

@@ -76,4 +76,13 @@ public interface Player extends HumanEntity, CommandSender {
      * @param sneak true if player should appear sneaking
      */
     public void setSneaking(boolean sneak);
+
+    /**
+     * Forces an update of the player's entire inventory.
+     *
+     * @return
+     *
+     * @deprecated This method should not be relied upon as it is a temporary work-around for a larger, more complicated issue.
+     */
+    public void updateInventory();
 }